The mains fuse is located at the mains inlet on the rear panel of the A-100 frame (exception: the older suitcase version A-100P6 with mains inlet at the front). One has to disconnect the mains cable and remove the fuse holder (e.g. with the aid of a screw driver).

The fuse holder is a small black plastic part that is inserted into the mains inlet. The following document shows the fuse holder in detail: A-100 Sicherungshalter. The table below shows the values for the fuses depending upon the case type and mains voltage.

 Cases with A-100PSU3 / manufactured from about early in 2016

It's essential that time lag (slow blow) fuses  5x20 mm have to be used ! Usually the type of response is abbreviated by a character on the metallic ring of the fuse:  F (fast), M (medium) or T (time lag = slow blow). A fuse coded "T" has to be used ! Medium or fast fast fuses are unsuitable and will blow.

In addition the A-100PSU3 has a separate +5V fuse in the secondary circuit available. If only the +5V are missing probably this fuse is blown (because of overload, short circuit, faulty module etc.). The fuse is located on the A-100PSU3 pc board near the four +5V terminals.
To reach the fuse it may be necessary to remove the power supply cover (2 screws). It's essential that the mains cable is disconnected before the cover is removed ! It's not sufficient to operate the mains switch only !
From the factory 2A (fast) are installed. The value can be increased up to 4A (fast) if the total current consumption at +5V is more than 2A. But this is recommended only of really a higher current than 2A is required. The value of this fuse is independent from the mains voltage (i.e. the same for 115V and 230V mains voltage).

Cases with A-100PSU2 / manufactured until end of 2015

It's essential that time lag (slow blow) fuses  5x20 mm have to be used ! Usually the type of response is abbreviated by a character on the metallic ring of the fuse:  F (fast), M (medium) or T (time lag = slow blow). A fuse coded "T" has to be used ! Medium or fast fast fuses are unsuitable and will blow. The reason for the time lag fuses is the high transient current during power on that is ignored by the slow fuses. This transient current is much higher for ring core/toroid transformer than for normal transformers.

Cases with A-100PSU1 (A-100NT12) /  manufactured until about 2003

If you still own an older A-100 frame or suitcase with the old version of the power supply (A-100NT12, 650mA output current, manufactured until about 2001) a fuse with 125 mA (230V) / 250 mA (115V) is required.  Time lag (slow blow) fuses  5x20 mm have to be used ! Usually the type of response is abbreviated by a character on the metallic ring of the fuse:  F (fast), M (medium) or T (time lag = slow blow). A fuse coded "T" has to be used ! Medium or fast fast fuses are unsuitable and will blow.

Case A-100LC3 and A-100 DIY kits

Even the A-100 DIY kits and the A-100LC3 contain fuses. There is no difference between 115V and 230V for the fuse values as these fuses are used to protect the secondary circuits of the supplies (i.e. the low voltages). The specified values are valid for the transformers and wall outlet power supplies that are available from us for the DIY kits. If other transformers or supplies are used the values have to be changed depending on the specification of the transformer or supply. In this case the values specified in the table are maximum values. If a transformer or supply with lower power is used the fuse values should be changed according to the specification of the transformer or supply.